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URL https://opencores.org/ocsvn/rtfsimpleuart/rtfsimpleuart/trunk

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/rtfsimpleuart/trunk/rtl/verilog/rtfSimpleUartRx.v
1,81 → 1,82
/* ============================================================================
2011 Robert Finch
robfinch@<remove>sympatico.ca
// ============================================================================
// (C) 2011,2013 Robert Finch
// All rights reserved.
// robfinch@<remove>finitron.ca
//
// rtfSimpleUartRx.v
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the <organization> nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Simple UART receiver core
// Features:
// false start bit detection
// framing error detection
// overrun state detection
// resynchronization on every character
// fixed format 1 start - 8 data - 1 stop bits
// uses 16x clock rate
//
// This core may be used as a standalone peripheral
// on a SoC bus if all that is desired is recieve
// capability. It requires a 16x baud rate clock.
//
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |WISHBONE Datasheet
// |WISHBONE SoC Architecture Specification, Revision B.3
// |
// |Description: Specifications:
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |General Description: simple serial UART receiver
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Supported Cycles: SLAVE,READ
// | SLAVE,BLOCK READ
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Data port, size: 8 bit
// |Data port, granularity: 8 bit
// |Data port, maximum operand size: 8 bit
// |Data transfer ordering: Undefined
// |Data transfer sequencing: Undefined
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Clock frequency constraints: none
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Supported signal list and Signal Name WISHBONE equiv.
// |cross reference to equivalent ack_o ACK_O
// |WISHBONE signals
// | clk_i CLK_I
// | rst_i RST_I
// | dat_o(7:0) DAT_O()
// | cyc_i CYC_I
// | stb_i STB_I
// | we_i WE_I
// |
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Special requirements:
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//
// Ref: Spartan3 -4
// 27 LUTs / 24 slices / 170 MHz
//==============================================================================
 
rtfSimpleUartRx.v
 
This source code is available for evaluation and validation purposes
only. This copyright statement and disclaimer must remain present in
the file.
 
 
NO WARRANTY.
THIS Work, IS PROVIDEDED "AS IS" WITH NO WARRANTIES OF ANY KIND, WHETHER
EXPRESS OR IMPLIED. The user must assume the entire risk of using the
Work.
 
IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES WHATSOEVER RELATING TO
THE USE OF THIS WORK, OR YOUR RELATIONSHIP WITH THE AUTHOR.
 
IN ADDITION, IN NO EVENT DOES THE AUTHOR AUTHORIZE YOU TO USE THE WORK
IN APPLICATIONS OR SYSTEMS WHERE THE WORK'S FAILURE TO PERFORM CAN
REASONABLY BE EXPECTED TO RESULT IN A SIGNIFICANT PHYSICAL INJURY, OR IN
LOSS OF LIFE. ANY SUCH USE BY YOU IS ENTIRELY AT YOUR OWN RISK, AND YOU
AGREE TO HOLD THE AUTHOR AND CONTRIBUTORS HARMLESS FROM ANY CLAIMS OR
LOSSES RELATING TO SUCH UNAUTHORIZED USE.
 
 
Simple UART receiver core
Features:
false start bit detection
framing error detection
overrun state detection
resynchronization on every character
fixed format 1 start - 8 data - 1 stop bits
uses 16x clock rate
This core may be used as a standalone peripheral
on a SoC bus if all that is desired is recieve
capability. It requires a 16x baud rate clock.
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|WISHBONE Datasheet
|WISHBONE SoC Architecture Specification, Revision B.3
|
|Description: Specifications:
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|General Description: simple serial UART receiver
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Supported Cycles: SLAVE,READ
| SLAVE,BLOCK READ
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Data port, size: 8 bit
|Data port, granularity: 8 bit
|Data port, maximum operand size: 8 bit
|Data transfer ordering: Undefined
|Data transfer sequencing: Undefined
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Clock frequency constraints: none
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Supported signal list and Signal Name WISHBONE equiv.
|cross reference to equivalent ack_o ACK_O
|WISHBONE signals
| clk_i CLK_I
| rst_i RST_I
| dat_o(7:0) DAT_O()
| cyc_i CYC_I
| stb_i STB_I
| we_i WE_I
|
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Special requirements:
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
Ref: Spartan3 -4
27 LUTs / 24 slices / 170 MHz
============================================================================ */
 
`define IDLE 0
`define CNT 1
 
/rtfsimpleuart/trunk/rtl/verilog/rtfSimpleUartTx.v
1,75 → 1,76
/* ============================================================================
2011 Robert Finch
robfinch@<remove>sympatico.ca
// ============================================================================
// (C) 2011,2013 Robert Finch
// All rights reserved.
// robfinch@<remove>finitron.ca
//
// rtfSimpleUartTx.v
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the <organization> nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Simple uart transmitter core.
// Features:
// Fixed format 1 start - 8 data - 1 stop bits
//
//
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |WISHBONE Datasheet
// |WISHBONE SoC Architecture Specification, Revision B.3
// |
// |Description: Specifications:
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |General Description: simple serial UART transmitter
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Supported Cycles: SLAVE,WRITE
// | SLAVE,BLOCK WRITE
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Data port, size: 8 bit
// |Data port, granularity: 8 bit
// |Data port, maximum operand size: 8 bit
// |Data transfer ordering: Undefined
// |Data transfer sequencing: Undefined
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Clock frequency constraints: none
// | Baud Generates by X16 or X8 CLK_I depends on baud8x pin
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Supported signal list and Signal Name WISHBONE equiv.
// |cross reference to equivalent ack_o ACK_O
// |WISHBONE signals
// | clk_i CLK_I
// | rst_i RST_I
// | dat_i[7:0] DAT_I()
// | cyc_i CYC_I
// | stb_i STB_I
// | we_i WE_I
// |
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Special requirements:
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//
//
// REF: Spartan3 - 4
// 30 LUTs / 23 slices / 165MHz
//============================================================================ */
 
rtfSimpleUartTx.v
 
This source code is available for evaluation and validation purposes
only. This copyright statement and disclaimer must remain present in
the file.
 
 
NO WARRANTY.
THIS Work, IS PROVIDEDED "AS IS" WITH NO WARRANTIES OF ANY KIND, WHETHER
EXPRESS OR IMPLIED. The user must assume the entire risk of using the
Work.
 
IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES WHATSOEVER RELATING TO
THE USE OF THIS WORK, OR YOUR RELATIONSHIP WITH THE AUTHOR.
 
IN ADDITION, IN NO EVENT DOES THE AUTHOR AUTHORIZE YOU TO USE THE WORK
IN APPLICATIONS OR SYSTEMS WHERE THE WORK'S FAILURE TO PERFORM CAN
REASONABLY BE EXPECTED TO RESULT IN A SIGNIFICANT PHYSICAL INJURY, OR IN
LOSS OF LIFE. ANY SUCH USE BY YOU IS ENTIRELY AT YOUR OWN RISK, AND YOU
AGREE TO HOLD THE AUTHOR AND CONTRIBUTORS HARMLESS FROM ANY CLAIMS OR
LOSSES RELATING TO SUCH UNAUTHORIZED USE.
 
 
Simple uart transmitter core.
Features:
Fixed format 1 start - 8 data - 1 stop bits
 
 
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|WISHBONE Datasheet
|WISHBONE SoC Architecture Specification, Revision B.3
|
|Description: Specifications:
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|General Description: simple serial UART transmitter
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Supported Cycles: SLAVE,WRITE
| SLAVE,BLOCK WRITE
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Data port, size: 8 bit
|Data port, granularity: 8 bit
|Data port, maximum operand size: 8 bit
|Data transfer ordering: Undefined
|Data transfer sequencing: Undefined
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Clock frequency constraints: none
| Baud Generates by X16 or X8 CLK_I depends on baud8x pin
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Supported signal list and Signal Name WISHBONE equiv.
|cross reference to equivalent ack_o ACK_O
|WISHBONE signals
| clk_i CLK_I
| rst_i RST_I
| dat_i[7:0] DAT_I()
| cyc_i CYC_I
| stb_i STB_I
| we_i WE_I
|
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Special requirements:
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 
REF: Spartan3 - 4
30 LUTs / 23 slices / 165MHz
============================================================================ */
 
module rtfSimpleUartTx(
// WISHBONE SoC bus interface
input rst_i, // reset
/rtfsimpleuart/trunk/rtl/verilog/edge_det.v
1,60 → 1,59
/* ============================================================================
2007 Robert Finch
rob@birdcomputer.ca
 
edge_det.v
 
This source code is available for evaluation and validation purposes
only. This copyright statement and disclaimer must remain present in
the file.
 
 
NO WARRANTY.
THIS Work, IS PROVIDEDED "AS IS" WITH NO WARRANTIES OF ANY KIND, WHETHER
EXPRESS OR IMPLIED. The user must assume the entire risk of using the
Work.
 
IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES WHATSOEVER RELATING TO
THE USE OF THIS WORK, OR YOUR RELATIONSHIP WITH THE AUTHOR.
 
IN ADDITION, IN NO EVENT DOES THE AUTHOR AUTHORIZE YOU TO USE THE WORK
IN APPLICATIONS OR SYSTEMS WHERE THE WORK'S FAILURE TO PERFORM CAN
REASONABLY BE EXPECTED TO RESULT IN A SIGNIFICANT PHYSICAL INJURY, OR IN
LOSS OF LIFE. ANY SUCH USE BY YOU IS ENTIRELY AT YOUR OWN RISK, AND YOU
AGREE TO HOLD THE AUTHOR AND CONTRIBUTORS HARMLESS FROM ANY CLAIMS OR
LOSSES RELATING TO SUCH UNAUTHORIZED USE.
 
 
Notes:
 
Edge detector
This little core detects an edge (positive, negative, and
either) in the input signal.
 
Verilog 1995
Webpack 9.2 xc3S1000-4ft256
3 LUTs / 2 slices / 9.1ns
============================================================================ */
 
module edge_det(rst, clk, ce, i, pe, ne, ee);
input rst; // reset
input clk; // clock
input ce; // clock enable
input i; // input signal
output pe; // positive transition detected
output ne; // negative transition detected
output ee; // either edge (positive or negative) transition detected
 
reg ed;
always @(posedge clk)
if (rst)
ed <= 1'b0;
else if (ce)
ed <= i;
 
assign pe = ~ed & i; // positive: was low and is now high
assign ne = ed & ~i; // negative: was high and is now low
assign ee = ed ^ i; // either: signal is now opposite to what it was
endmodule
// ============================================================================
// (C) 2007,2013 Robert Finch
// All rights reserved.
// robfinch@<remove>finitron.ca
//
// edge_det.v
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the <organization> nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Notes:
//
// Edge detector
// This little core detects an edge (positive, negative, and
// either) in the input signal.
//
// Verilog 1995
// ============================================================================
 
module edge_det(rst, clk, ce, i, pe, ne, ee);
input rst; // reset
input clk; // clock
input ce; // clock enable
input i; // input signal
output pe; // positive transition detected
output ne; // negative transition detected
output ee; // either edge (positive or negative) transition detected
 
reg ed;
always @(posedge clk)
if (rst)
ed <= 1'b0;
else if (ce)
ed <= i;
 
assign pe = ~ed & i; // positive: was low and is now high
assign ne = ed & ~i; // negative: was high and is now low
assign ee = ed ^ i; // either: signal is now opposite to what it was
endmodule
/rtfsimpleuart/trunk/rtl/verilog/rtfSimpleUart.v
1,227 → 1,227
/* ============================================================================
2007,2011 Robert Finch
robfinch@<remove>sympatico.ca
// ============================================================================
// (C) 2007,2011,2013 Robert Finch
// All rights reserved.
// robfinch@<remove>finitron.ca
//
// rtfSimpleUart.v
// Basic uart with baud rate generator based on a harmonic
// frequency synthesizer.
//
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the <organization> nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//
// To use:
//
// Set the pClkFreq parameter to the frequency of the system
// clock (clk_i). This can be done when the core is instanced.
//
// 1) set the baud rate value in the clock multiplier
// registers (CM1,2,3). A default multiplier value may
// be specified using the pClkMul parameter, so it
// doesn't have to be programmed at run time. (Note the
// pBaud parameter may also be set, but it doesn't work
// in all cases due to arithmetic limitations).
// 2) enable communication by activating the rts, and
// dtr signals in the modem control register. These
// signals are defaulted to be active on reset, so they
// may not need to be set. The pRts and pDtr parameters
// may be used to change the default setting.
// 3) use interrupts or poll the status register to
// determine when to transmit or receive a byte of data
// 4) read / write the transmit / recieve data buffer
// for communication.
//
// Notes:
// This core only supports a single transmission /
// reception format: 1 start, 8 data, and 1 stop bit (no
// parity).
// The baud rate generator uses a 24 bit harmonic
// frequency synthesizer. Compute the multiplier value
// as if a 32 bit value was needed, then take the upper
// 24 bits of the value. (The number of significant bits
// in the value determine the minimum frequency
// resolution or the precision of the value).
//
// baud rate * 16
// value = -----------------------
// (clock frequency / 2^32)
//
// eg 38400 * 16
// value = -----------------------
// (28.63636MHz / 2^32)
//
// = 92149557.65
// = 057E1736 (hex)
//
//
// taking the upper 24 bits
// top 24 = 057E17
// = 359959
//
// so the value needed to be programmed into the register
// for 38.4k baud is 57E17 (hex)
// eg CM0 = 0 (not used)
// CM1 = 17 hex
// CM2 = 7E hex
// CM3 = 05 hex
//
//
// Register Description
//
// reg
// 0 read / write (RW)
// TRB - transmit / receive buffer
// transmit / receive buffer
// write - write to transmit buffer
// read - read from receive buffer
//
// 1 read only (RO)
// LS - line status register
// bit 0 = receiver not empty, this bit is set if there is
// any data available in the receiver fifo
// bit 1 = overrun, this bit is set if receiver overrun occurs
// bit 3 = framing error, this bit is set if there was a
// framing error with the current byte in the receiver
// buffer.
// bit 5 = transmitter not full, this bit is set if the transmitter
// can accept more data
// bit 6 = transmitter empty, this bit is set if the transmitter is
// completely empty
//
// 2 MS - modem status register (RO)
// writing to the modem status register clears the change
// indicators, which should clear a modem status interrupt
// bit 3 = change on dcd signal
// bit 4 = cts signal level
// bit 5 = dsr signal level
// bit 6 = ri signal level
// bit 7 = dcd signal level
//
// 3 IS - interrupt status register (RO)
// bit 0-4 = mailbox number
// bit 0,1 = 00
// bit 2-4 = encoded interrupt value
// bit 5-6 = not used, reserved
// bit 7 = 1 = interrupt pending, 0 = no interrupt
//
// 4 IE - interrupt enable register (RW)
// bit 0 = receive interrupt (data present)
// bit 1 = transmit interrupt (data empty)
// bit 3 = modem status (dcd) register change
// bit 5-7 = unused, reserved
//
// 5 FF - frame format register (RW)
// this register doesn't do anything in the simpleUart
// but is reserved for compatiblity with the more
// advanced uart
//
// 6 MC - modem control register (RW)
// bit 0 = dtr signal level output
// bit 1 = rts signal level output
//
// 7 - control register
// bit 0 = hardware flow control,
// when this bit is set, the transmitter output is
// controlled by the cts signal line automatically
//
//
// * Clock multiplier steps the 16xbaud clock frequency
// in increments of 1/2^32 of the clk_i input using a
// harmonic frequency synthesizer
// eg. to get a 9600 baud 16x clock (153.6 kHz) with a
// 27.175 MHz clock input,
// value = upper24(9600 * 16 / (27.175MHz / 2^32))
// Higher frequency baud rates will exhibit more jitter
// on the 16x clock, but this will mostly be masked by the
// 16x clock factor.
//
// 8 CM0 - Clock Multiplier byte 0 (RW)
// this is the least significant byte
// of the clock multiplier value
// this register is not used unless the clock
// multiplier is set to contain 32 bit values
//
// 9 CM1 - Clock Multiplier byte 1 (RW)
// this is the third most significant byte
// of the clock multiplier value
// this register is not used unless the clock
// multiplier is set to contain 24 or 32 bit values
//
// 10 CM2 - Clock Multiplier byte 2 (RW)
// this is the second most significant byte of the clock
// multiplier value
//
// 11 CM3 - Clock Multiplier byte 3 (RW)
// this is the most significant byte of the multiplier value
//
// 12 FC - Fifo control register (RW)
// this register doesnt' do anything in the simpleUart
// but is reserved for compatibility with the more
// advanced uart
//
// 13-14 reserved registers
//
// 15 SPR - scratch pad register (RW)
//
//
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |WISHBONE Datasheet
// |WISHBONE SoC Architecture Specification, Revision B.3
// |
// |Description: Specifications:
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |General Description: simple UART core
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Supported Cycles: SLAVE,READ/WRITE
// | SLAVE,BLOCK READ/WRITE
// | SLAVE,RMW
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Data port, size: 8 bit
// |Data port, granularity: 8 bit
// |Data port, maximum operand size: 8 bit
// |Data transfer ordering: Undefined
// |Data transfer sequencing: Undefined
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Clock frequency constraints: none
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Supported signal list and Signal Name WISHBONE equiv.
// |cross reference to equivalent ack_o ACK_O
// |WISHBONE signals adr_i[3:0] ADR_I()
// | clk_i CLK_I
// | rst_i RST_I()
// | dat_i(7:0) DAT_I()
// | dat_o(7:0) DAT_O()
// | cyc_i CYC_I
// | stb_i STB_I
// | we_i WE_I
// |
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// |Special requirements:
// +- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
//
//=============================================================================
 
rtfSimpleUart.v
Basic uart with baud rate generator based on a harmonic
frequency synthesizer.
 
This source code is available for evaluation and validation purposes
only. This copyright statement and disclaimer must remain present in
the file.
 
 
NO WARRANTY.
THIS Work, IS PROVIDEDED "AS IS" WITH NO WARRANTIES OF ANY KIND, WHETHER
EXPRESS OR IMPLIED. The user must assume the entire risk of using the
Work.
 
IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES WHATSOEVER RELATING TO
THE USE OF THIS WORK, OR YOUR RELATIONSHIP WITH THE AUTHOR.
 
IN ADDITION, IN NO EVENT DOES THE AUTHOR AUTHORIZE YOU TO USE THE WORK
IN APPLICATIONS OR SYSTEMS WHERE THE WORK'S FAILURE TO PERFORM CAN
REASONABLY BE EXPECTED TO RESULT IN A SIGNIFICANT PHYSICAL INJURY, OR IN
LOSS OF LIFE. ANY SUCH USE BY YOU IS ENTIRELY AT YOUR OWN RISK, AND YOU
AGREE TO HOLD THE AUTHOR AND CONTRIBUTORS HARMLESS FROM ANY CLAIMS OR
LOSSES RELATING TO SUCH UNAUTHORIZED USE.
 
 
To use:
Set the pClkFreq parameter to the frequency of the system
clock (clk_i). This can be done when the core is instanced.
1) set the baud rate value in the clock multiplier
registers (CM1,2,3). A default multiplier value may
be specified using the pClkMul parameter, so it
doesn't have to be programmed at run time. (Note the
pBaud parameter may also be set, but it doesn't work
in all cases due to arithmetic limitations).
2) enable communication by activating the rts, and
dtr signals in the modem control register. These
signals are defaulted to be active on reset, so they
may not need to be set. The pRts and pDtr parameters
may be used to change the default setting.
3) use interrupts or poll the status register to
determine when to transmit or receive a byte of data
4) read / write the transmit / recieve data buffer
for communication.
 
Notes:
This core only supports a single transmission /
reception format: 1 start, 8 data, and 1 stop bit (no
parity).
The baud rate generator uses a 24 bit harmonic
frequency synthesizer. Compute the multiplier value
as if a 32 bit value was needed, then take the upper
24 bits of the value. (The number of significant bits
in the value determine the minimum frequency
resolution or the precision of the value).
 
baud rate * 16
value = -----------------------
(clock frequency / 2^32)
eg 38400 * 16
value = -----------------------
(28.63636MHz / 2^32)
= 92149557.65
= 057E1736 (hex)
taking the upper 24 bits
top 24 = 057E17
= 359959
so the value needed to be programmed into the register
for 38.4k baud is 57E17 (hex)
eg CM0 = 0 (not used)
CM1 = 17 hex
CM2 = 7E hex
CM3 = 05 hex
 
 
Register Description
 
reg
0 read / write (RW)
TRB - transmit / receive buffer
transmit / receive buffer
write - write to transmit buffer
read - read from receive buffer
 
1 read only (RO)
LS - line status register
bit 0 = receiver not empty, this bit is set if there is
any data available in the receiver fifo
bit 1 = overrun, this bit is set if receiver overrun occurs
bit 3 = framing error, this bit is set if there was a
framing error with the current byte in the receiver
buffer.
bit 5 = transmitter not full, this bit is set if the transmitter
can accept more data
bit 6 = transmitter empty, this bit is set if the transmitter is
completely empty
 
2 MS - modem status register (RO)
writing to the modem status register clears the change
indicators, which should clear a modem status interrupt
bit 3 = change on dcd signal
bit 4 = cts signal level
bit 5 = dsr signal level
bit 6 = ri signal level
bit 7 = dcd signal level
 
3 IS - interrupt status register (RO)
bit 0-4 = mailbox number
bit 0,1 = 00
bit 2-4 = encoded interrupt value
bit 5-6 = not used, reserved
bit 7 = 1 = interrupt pending, 0 = no interrupt
 
4 IE - interrupt enable register (RW)
bit 0 = receive interrupt (data present)
bit 1 = transmit interrupt (data empty)
bit 3 = modem status (dcd) register change
bit 5-7 = unused, reserved
 
5 FF - frame format register (RW)
this register doesn't do anything in the simpleUart
but is reserved for compatiblity with the more
advanced uart
 
6 MC - modem control register (RW)
bit 0 = dtr signal level output
bit 1 = rts signal level output
 
7 - control register
bit 0 = hardware flow control,
when this bit is set, the transmitter output is
controlled by the cts signal line automatically
 
 
* Clock multiplier steps the 16xbaud clock frequency
in increments of 1/2^32 of the clk_i input using a
harmonic frequency synthesizer
eg. to get a 9600 baud 16x clock (153.6 kHz) with a
27.175 MHz clock input,
value = upper24(9600 * 16 / (27.175MHz / 2^32))
Higher frequency baud rates will exhibit more jitter
on the 16x clock, but this will mostly be masked by the
16x clock factor.
 
8 CM0 - Clock Multiplier byte 0 (RW)
this is the least significant byte
of the clock multiplier value
this register is not used unless the clock
multiplier is set to contain 32 bit values
 
9 CM1 - Clock Multiplier byte 1 (RW)
this is the third most significant byte
of the clock multiplier value
this register is not used unless the clock
multiplier is set to contain 24 or 32 bit values
 
10 CM2 - Clock Multiplier byte 2 (RW)
this is the second most significant byte of the clock
multiplier value
 
11 CM3 - Clock Multiplier byte 3 (RW)
this is the most significant byte of the multiplier value
 
12 FC - Fifo control register (RW)
this register doesnt' do anything in the simpleUart
but is reserved for compatibility with the more
advanced uart
13-14 reserved registers
 
15 SPR - scratch pad register (RW)
 
 
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|WISHBONE Datasheet
|WISHBONE SoC Architecture Specification, Revision B.3
|
|Description: Specifications:
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|General Description: simple UART core
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Supported Cycles: SLAVE,READ/WRITE
| SLAVE,BLOCK READ/WRITE
| SLAVE,RMW
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Data port, size: 8 bit
|Data port, granularity: 8 bit
|Data port, maximum operand size: 8 bit
|Data transfer ordering: Undefined
|Data transfer sequencing: Undefined
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Clock frequency constraints: none
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Supported signal list and Signal Name WISHBONE equiv.
|cross reference to equivalent ack_o ACK_O
|WISHBONE signals adr_i[3:0] ADR_I()
| clk_i CLK_I
| rst_i RST_I()
| dat_i(7:0) DAT_I()
| dat_o(7:0) DAT_O()
| cyc_i CYC_I
| stb_i STB_I
| we_i WE_I
|
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|Special requirements:
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 
Ref. Spartan3 -4
117 LUTs / 87 slices / 133 MHz
============================================================================ */
 
`define UART_TRB 4'd0 // transmit/receive buffer
`define UART_LS 4'd1 // line status register
`define UART_MS 4'd2 // modem status register

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